One key factor: Determining the nuances of how capacitors handle expected ripple currents

Examine a dc link capacitor’s ac ripple current and you’ll realize it arises from two main contributors: the incoming current from the energy source and the current drawn by the inverter. Of course, capacitors cannot pass dc current; thus, dc current only flows from the source to the inverter, bypassing the capacitor. Power factor correction (PFC) in the converter and/or regenerative energy flow in certain inverter topologies can complicate matters. But in all cases, instantaneous current is conserved at the three-current node of the dc link capacitor connection…

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